[B] BATEMAN P. T.: The distribution of values of the Euler function. Acta Arith. 21 (1972), 329-345. MR 0302586 | Zbl 0217.31901

[C-F] Algebraic Number Theory. (J. W. S. Cassels and A. Frohlich, eds.), Academic Press, 1967. MR 0215665 | Zbl 0153.07403

[Cz] CZOGALA A.: On reciprocity equivalence of quadratic number fields. Acta Arith. 58 (1991), 27-46. MR 1111088 | Zbl 0733.11012

[J-M] JAKUBEC S., MARKO F.: Witt equivalence classes of quartic number fields. Math. Comp. 58 (1992), 355-368. MR 1094952 | Zbl 0742.11022

[L] LAM T. Y.: The Algebraic Theory of Quadratic Forms. Benjamin/Cummings, Reading-Mass, 1980. MR 0634798 | Zbl 0437.10006

[M-P] MAIER H., POMERANCE C.: On the number of distinct values of Euler's Φ-function. Acta Arith. 49 (1988), 263-275. MR 0932525

[P-S-C-L] PERLIS R., SZYMICZEK K., CONNER P. E., LITHERLAND R.: Matching Witts with global fields. Preprint (1989).

[Sc] SCHINZEL A.: Sur l'équation Φ(x) = m. Elem. Math. 11 (1956), 75-78. MR 0080114

[Si] SIERPIŃSKI W.: Elementary Theory of Numbers. (A. Schinzel, ed.), PWN and North-Holland, Warszawa - Amsterdam - Oxford - New York, 1987. MR 0930670

[SI] SZYMICZEK K.: Problem No. 12. In: Conf. Report 9-th Czechoslovak Colloq. Number Theory, Račkova Dolina 1989, Masarykova univerzita, Brno, 1989.

[S2] SZYMICZEK K.: Matching Witts locally and globally. Math. Slovaca 41 (1991), 315-330. MR 1126669 | Zbl 0766.11023

[S3] SZYMICZEK K.: Witt equivalence of global fields. Comm. Algebra 19 (1991), 1125-1149. MR 1102331 | Zbl 0724.11020

[W] WEISS E.: Algebraic Number Theory. Chelsea Publishing Co., New York, 1976. MR 0417112 | Zbl 0348.12101